Search Documents

By Enga B. E

Following considerable laboratory studies concerning diesel particulate control systems for underground use, a Canadian program was initiated to implement practical, real-life systems. This program covers the application in seven mines throughout Canada, of a particulate control system, to 14 engine models from four engine manufacturers in 18 different vehicle types, for a total of 23 vehicles. Partially funded by the Canadian National Research Council (NRC), this program required detailed analysis of operating cycles, maintenance variabilities and installation problems. This paper summarizes the work carried out to date to define real-world targets and the success achieved so far in attaining practical underground particulate control.

Jan 1, 1988

By Michael J. Gallagher

Diamond-bit performance data accumulated by the Bureau of Mines in core-drilling limestone and dolomite show that the physical characteristics of the diamonds and the sizes and types of bits used are economically significant. An analysis of the data establishes one trend of particular significance to those engaged in core drilling: Bits set with small, low-quality drill bort are the most economical. Detailed analysis of the factors that affect diamond-bit performance, such as size and quality of diamonds, sizes and types of bits, percentage of core recovered, and physical characteristics of bit matrices are assessed in the tables, bar charts, and discussion.

Jan 1, 1958

By J. J. Barakso, S. J. Horsky, H. V. Warren

"A review of past and present biogeochemical studies is given. Early and more recent analytical procedures are described and compared. Tables 1-5 give silver concentrations in various organs of some plant species at different localities. Table 6 and conclusions provide guidelines for exploring for silver using biogeochemistry.IntroductionBiogeochemistry has been shown to be a useful tool in the search for gold deposits, especially those of the disseminated type (Warren and Barakso 1982). The purpose of this paper is to demonstrate that biogeochemistry can also be of assistance in searching for silver concentrations buried by as much as twenty feet of overburden without inflicting any damage on the environment."

Jan 1, 1984

By Blight P

There is today widespread concern about the future of the mining industry. In attempting to understand the underlying causes the paper probes in some detail, the long term structural changes affecting growth of metal demand and the development of excess mineral supply capacity. This examination reveals an industry characterised by an unfavourable combination of high barriers to exit and low entry barriers. While rising entry barriers are expected to herald some improvement in the profitability of mining over the next decade, this adjustment is likely to be slow and will require a more economically rational assessment of the industry by corporations and governments Alike.

Jan 1, 1986

By Steve Iverson, Jeffrey C. Johnson, Henry Rodriguez, Rene Rodriguez, Michael Lhamond

To reduce fatalities resulting from personnel falling into voids formed above feeders in coal piles, the National Institute for Occupational Safety and Health at the Spokane Research Laboratory established a project to monitor coal surge piles to detect the formation of voids. A resistivity imaging method has been developed by GECOH Exploration, of Lexington, KY, in which a geophysical technique known as vertical electrical sounding (VES) is used to scan for these voids. VES operates by measuring the electrical field produced by a current in the ground at the bottom of the coal pile. This paper summarizes the results obtained from a field-scale test and shows that mapping voids within a coal pile is possible.

By A. L. Putz, G. Ladouceur, A. R. Laplante

A laboratory centrifugal concentrator was used to evaluate two gravity circuit configurations treating a flash flotation concentrate at a Canadian gold mill. The Initial circuit consisted of a 76 cm (30 Inch) plant Knelson Concentrator (PKC) for coarse gold removal. Later, a hydroseparator and spiral were Installed, with the hydroseparator underflow feeding the spiral and the spiral tailings plus hydroseparator overfiow reporting to a 51 cm (20 Inch) PKC. Gold recovery In the 76 cm PKC averaged 45%. Gold was recovered consistently In all size fractions greater than 38 µm, where recovery dropped to 22% for the -38 µm material. Changing the circuit to Include the hydroseparator and spiral decreased the Knelson unit recovery to less than 17%. The decrease was attributed to the spiral which recovered much of the free gold ahead of the Knelson and to changes In the mill feed (free gold portions were finer and less abundant). The spiral demonstrated erratic behaviour although It still recovered significant coarse gold (+75 µm) yielding unit recoveries of 18-44%. Although mechanical difficulties were experienced with the 76 cm PKC, Its performance was superior to that of the hydroseparator, spiral and 51 cm PKC configuration. Much of the gold In the ball mill recirculating load was found to be too coarse for significant recovery In the flash flotation cell and should be recovered by gravity from the cyclone underflow or ball mill discharge. The LKC proved to be a successful device to evaluate gravity recoverable gold content. Dilution of test samples with silica further enhanced this methodology.

Jan 1, 1993

By C. F. Meyer

The recirculation of mine air in an underground colliery, has always been regarded as a hazardous practice in South African collieries. The Mines and Works Act and Regulations states that fresh air, flowing Into an underground section, must flow out directly into the return airways after being utilized once in the section. One of the largest producing underground collieries in South Africa, Initiated a project on controlled recirculation with the permission of the South African Government Mining Engineer. The project involves the recirculation of 65 m3/s of air inside a ventilation district which serves a total of six production areas. The aim of the project was to increase the airflow to the sections without altering the existing ventilation system. Tracer gas studies were carried out to determine the actual distribution of the recirculated air to the individual areas. The results showed that an effective 54,18 m3/s of the recirculated 65 m3/s reaches the sections. This gives an air utilization figure of 83,4 per cent. Dust surveys were also carried out as part of the project to determine the effect of the recirculation of the return air on airborne dust levels. The results showed that the dust levels remained constant in the main intake and return airways and that no hazardous situation was being created. The project proved to be successful and showed that controlled recirculation can be executed and used as a solution for the supply of air to sections without endangering any lives.

Jan 1, 1993

Oceanographers are tooling up. Back of the build-up is Navy defense work and private business. Business is dipping toes in the ocean gingerly and not sure whether the motivation is based on logic or intuition. The problem is that new business opportunities in the oceans could explode rather than evolve. The question is when. At stake for earthlings are food supplies, mineral resources, oil and gas, weather forecasting, navigational systems, shore erosion control and sewage disposal, as primary targets. "Twenty years ago, offshore oil seemed a remote possibility for economic exploitation but today it is a reality. It became a reality largely because of the development of practical ocean seismic equipment and drilling platforms. Today the oil industry is looking at submerged-type drilling rigs. Mineral exploration in the sea is more expensive than on land now primarily because familiar land tools are being modified for sub- marine work." These were the ideas expressed by C. G. Welling of Lockheed Missiles & Space Co., at one of the many meetings that have taken place so far this year on development of marine resources. Welling's views indicate the rationale of companies that have already invested in the sea. Many companies, including those in mining, have observers who caution, "go slow." The continental shelfs and even the deep ocean floor represent to the mineral industries the age-old, enigmatic confrontation-is this the time to move? To no other industry, except Defense, are the results of correct timing so vital.

Jan 8, 1967

Over the past 15 years, Artificial Intelligence (AI) techniques have shown promise of providing the ability to capture `human intelligence' into a computer program. The sub-fields of Expert Systems and Artificial Neural Networks are finding increased use in industry to perform tasks previously considered the domain of human thinking. But, are these methods just a new type of software much like that of the past or is real magic hidden within the lines of code? Will this field continue to enjoy high growth rates and if so, what developments will we see in the near future? Which algorithms and methodologies will continue to grow? This paper discusses a number of paradigms which can be used to create successful applications. There are certain barriers; some psychological - some linked with knowledge acquisition, that must be overcome or avoided to ensure system performance. Development time also requires careful consideration before embarking on an Al project. The paper focusses on constructing goal-driven systems that transfer high-technology solutions from the research laboratory to the plant floor. Respect for system users is of paramount importance - whether their involvement is to access contained information or to participate in program maintenance as new knowledge becomes available. Examples of successful and unsuccessful AI implementation in Canadian industry and academia provide evidence of the importance of this issue. The paper also examines some current constraints on applying AI in the real-world. Among these problems are automated knowledge acquisition, methods to acquire data during run-time, real-time systems (hardware versus software), explanation and justification features and adaptive/leaning systems.

Jan 1, 1995

By F. P. Hassani, J. F. Boily, A. M. O. Mohamed, M. Hossein

The optimal geochemical parameters required to form ellringite in a lime-remediated site have been investigated with the use of thermodynamic modelling. The speciation of sulphate and 10 metals analyzed in samples of a mine tailing from northern Quebec was calculated with a computer model. The model also includes calcium, which would result from the addition of lime to the system. Two speciation calculations were done. The first one is a hypothetical speciation before the onset of precipitation and was used to devise the stability fields of minerals susceptible of forming in high pHs. The stability fields were determined by building activity ratio diagrams with sulphate, aluminum and calcium species concentrations for pHs ranging from 4 to 14. The investigation was carried out for a 25°C solution with an ionic strength less than 0.12. Thermodynamics predict that an optimal stability field for ettringite in the mine tailing samples containing 10-3 mol/L SO4-2,10-2 mol/L of AI(OH)4 requires at least 10-2mol/L of Ca+2 and a pH larger than 11.6. The sulphate contents of the mine tailing samples, however, limit the precipitation of ettringite and monosulphate could be an end-precipitate. The second speciation is in equilibrium with precipitates and provides information on the speciation of the residual metals. If ellringite could be precipitated as a stable form, it could serve as a sorptive agent for residual metals, and, due to its binding properties, consolidate tailings.

Jan 1, 1995

By Frederick M. Becket, Russell Franks

In a recent article,l which described the softening effect of columbium in plain high-chromium steels, the authors stated that their investigations had shown columbium to be also a particularly valuable inhibitor of intergranular corrosion in steels of the 18 per cent chromium, 8 per cent nickel type. It is the purpose of the present paper to record some of the results obtained through the introduction of columbium to the austenitic chromium-nickel steels. The damaging effects of this type of corrosion have become so widely known as to restrict considerably the applications of the steels under consideration, and therefore there is little question of the importance of the goal to be attained. Numerous contributions concerning the susceptibility of the austenitic chromium-nickel steels to intergranular corrosion have appeared during the past few years, and among others who have dealt constructively with the subject are such well-known authors as Strauss and Houdremont of Germany, Hatfield of England, and Bain in the United States. Different theories have been propounded as to the cause of intergranular corrosion, and various remedial measures have been proposed, the majority of which involve the use of addition agents. Titanium is the addition agent at present most generally employed, as suggested by Houdremont and modified as described by Bain, Aborn and Rutherford. Little has been published on the effects of holding these steels for long periods at the relatively lower temperatures in the presence of corroding media, and the effects have mot been fully realized by producer and consumer.

Jan 1, 1934

By Patiño E

Bioleaching is an established technology for the pre-treatment of refractory gold ores and concentrates and the leaching of whole ore copper heaps. In many cases, it offers economic, environmental and technical advantages over pressure oxidation and roasting. However for bioleaching to compete successfully with others pre-treatment processes it needs to be optimized with regard to the parameters that affect the bioleaching reactions and the growth of the microorganism involved. In this sense, this paper focus on the thermodynamic approach applied in bioleaching through of the definition of the growth system and it is thermodynamics analysis, the effect of heat production and energy dissipation on growth and thermodynamic analysis of growth kinetics and the effect of nonstandard conditions.

Sep 12, 2005

By M. Solomon

During the course of 2011 the nationalization of mines emerged as one of the most contentious and emotive political issues under review. Some four years after the African National Congress electoral conference held in Polokwane, which had led to a change of leadership within the country's ruling party, elements within the ruling party's youth league, which had been virulently supportive of the change in leadership, turned on the incumbent President, using the mining question as its rallying call. At issue was the expressed perception that mining has, since the country's democratization, not delivered the anticipated benefits to the population as a whole, continues to be the preserve of the capitalist element of the South African community, and is therefore in need of radical reform. Aspersions were made that transformation within the industry had failed dismally and that mining companies had not delivered against their commitments to the Mining Charter and social and labour plans. The debate became extremely vocal and heated, evoked dramatic and emotive opinions, and vigorous skirmishes on the matter were fought in the media over much of 2011 and into 2012.

Jan 1, 2013

By C. H. Bertoni

"The Superior Province of the Canadian Shield is the largest gold producing area within Archean greenstone rocks in the world, with total production of over 140 million ounces of gold. One hundred and fifty-five mines have individually produced more than 8,000 ounces, although only a relatively limited number of deposits (33) produced more than one million ounces of gold. The output from these 33 deposits accounts, however, for 85% of total gold production. The majority of grades (68%) ranges between 0.10 and 0.30 ounce per ton, and there is no linear relationship between grade and tonnage.Development of new gold mines reflects the history of gold prices. However, the response to the latest increase in gold prices was not as marked. It is concluded that gold deposits are becoming increasingly more difficult to find and new exploration techniques are urgently required.IntroductionWith most of its production coming out of the Superior Province, the Canadian Shield is the largest producer of gold from Archean greenstone rock s in the world. In total gold production, the Superior Province is surpassed only by the paleo-placers of Witwatersrand and the placers of the USSR (Anhaeusser, 1976). There has been no attempt so far to compile the historical production of the Province as a whole in a single document. The aim of this work is to fill this gap, not only for the convenience of having a complete list of gold producers, but, more importantly, as a basis on which to study the tonnage and grade characteristics of these deposits."

Jan 1, 1983

By Oscar F. Tangel

This paper outlines Canada's current status in world iron ore markets, and evaluates the prospects for the future. Estimates for the production, export and consumption of iron ore are given. Canada's major market will continue to be the United States, with the European Common Market countries, Japan and the United Kingdom also forming important outlets. The advantages held by Canada's major competitors in these latter three market areas are briefly discussed.

Jan 1, 1966

By J Beniscelli

Some words to honour Pedro:Pedro was among the few persons with a very high level in geology modelling, resource and reserve estimation, geometallurgy development, sampling theory applications and a deep understanding of the mining industry needs. He had brilliant ideas about new developments on economic geology. He was always looking at the long-term and proposed challenging questions a decade in advance on their solution.The fundamental aim of geometallurgy is to add economic value to the mining of mine resources by timely providing information and knowledge about the relevant metallurgical variables represented by their space models. In this manner, geometallurgy allows obtaining the optimal design of a project, mitigating processing risks, optimising and supporting production plans and identifying and assessing mining business opportunities.This paper describes the conceptual framework and geometallurgical definitions and some of Codelco’s experience during the last 15 years.

Sep 5, 2011

By A. Warczok

The mechanisms and kinetics of copper oxidation and reduction have been investigated in small scale thermal gravimetric experiments as well as in laboratory pilot scale, packed bed reactors. With blister copper flowing gravitationally down through a packed bed of ceramic particles, counter-current to low oxygen containing combustion gases, the rate of oxidation was found to be very high due to the large surface area created. Similarly, reduction by flowing copper through a packed bed of charcoal lead to rapid de-oxidation. Based on these laboratory measurements, fundamental rate data have been obtained. Modeling of industrial sized packed bed reactors using the laboratory results, opened up the possibilities of developing a new, very intensive, continuous process for copper fire refining. The developed mathematical model together with a computer process simulator, allowed for the design of the industrial-pilot installation to be built and tested at the ENAMI Paipote smelter in Chile.

Jan 1, 2007

By Carsten Rühlemann

Between 2008 and 2013, the German Federal Institute for Geosciences and Natural Resources (BGR) carried out five exploration cruises to the German license area in the eastern Pacific Nodule Belt. The first two expeditions were mainly dedicated to multibeam mapping to obtain an overview of the seafloor topography and acoustic backscatter strength. These data were used to identify ten to fourteen prospective nodule fields for potential future mining, which together cover about 16% of the total license area of 75,000 km2. During the last three cruises, three of these potential mining areas were explored in detail. For this purpose, the BGR developed a suite of exploration methods to map nodule size distributions and nodule abundances. These methods include acoustic surveys with vessel-based multibeam systems as well as near-bottom video mapping complemented by in situ sampling. The economically most valuable field has a size of ca. 2,000 km2, of which 34% is covered by medium to large nodules (> 4 cm long axis of nodules) with an average abundance of 22.4 kg/m2 and 44% is covered by small nodules (< 4 cm) with a mean abundance of 17.5 kg/m2. The total mass of nodules in this field comprises more than 30 million tons wet weight and could sustain deep-sea mining for at least 10 years.

Sep 14, 2011

By Miller B

General experience with improvement programs in the mining industry has been that, after some initial success, performance tends to deteriorate back to pre-improvement program level in a relatively short time after the spotlight is switched off.

Jan 1, 1998

By S. W. Jacobsz, F. O. Abimaje

Internal stability is a key consideration in the design and long-term performance of granular filters, as it precludes particle migration and internal erosion. This study evaluates the internal stability of coal discard material in coal co-disposal facilities. Reusing coal discards could reduce mine waste volumes and mitigate associated environmental impacts. However, coal discard material differs from most soils in terms of particle strength and density, with possible implications for hydraulic stability. Laboratory seepage tests were conducted on coal discard material under varying void ratios, subjected to a range of hydraulic gradients, and the results were used to confirm the applicability of the widely used empirical Kenney and Lau filter criterion to coal discard. Findings revealed that particle loss increased with higher void ratios. Nonetheless, particle migration remained minimal, with a maximum particle loss of only 0.2%, suggesting that coal discard exhibits sound internal stability under the tested conditions.

Jul 3, 2026